Re: Harpoon vs Hurricane:
Harpoon is a higher burst for its cost; 4x750=3000 for 10 OP, medium mount vs 9*500=4500 for 25 OP, large mount, and has a refire time of 8.25 vs 15. It has moderately better tracking than Hurricanes, but requires ECCM to reliably hit frigates and even some destroyers. It is great for rapidly overwhelming ships and I use tons of them! It pays for that by being much easier to shoot down (to the point where entire salvos of harpoons can't get through good PD, while hurricane submunitions often can), being much shorter ranged, and most crucially having much less ammo/total damage (9k vs 45k).
Hurricane has a somewhat low floor with the recent nerfs (going from 11 to 9 submunitions) and low accuracy without ECCM (with ECCM it is extremely accurate), but it has a high ceiling because it benefits more from ECCM, Racks, and the missile skill/its elite perk The Harpoon's low ammo is its weakness: with racks and the skill it has enough ammo to make a big difference in battles, but will still run out, and while the +50% firing rate is occasionally handy for rapid fire destruction, most of the time the missile is not firing because it lacks opportunity/would just waste itself, so that part of the skill is semi-wasted. The Hurricane has the ammo where the +50% fire rate is extremely valuable, almost like having an extra half weapon.
The Squall vs sabot is in a bit of a similar position: sabots are incredible burst and effective out of the box, but have short range and low ammo, while Squalls need ECCM but have the ammo where with +50% fire rate skill they are just an oppressive level of missiles.